Method and apparatus for transmitting/receiving uplink signaling information in a single carrier fdma system

ABSTRACT

A method and an apparatus method are provided for transmitting uplink information in a Single Carrier Frequency Division Multiple Access (SC-FDMA) wireless communication system. The method includes determining whether Acknowledgement/Negative Acknowledgement (ACK/NACK) information indicating whether or not downlink data has been received exists to be transmitted, if uplink data exists to be transmitted; multiplexing the uplink data and control information for the uplink data and transmitting multiplexed data including the uplink data and the control information, through a frequency resource allocated for the uplink data, if no ACK/NACK information exists; and multiplexing the uplink data, the control information for the uplink data, and the ACK/NACK information, and transmitting multiplexed data through the frequency resource allocated for the uplink data, if the ACK/NACK information exists. The ACK/NACK information is located adjacent to a pilot for the uplink data.

PRIORITY

This application is a Continuation of U.S. application Ser. No.11/650,896, which was filed in U.S. Patent and Trademark Office on Jan.8, 2007, and claims priority under 35 U.S.C. §119(a) to KoreanApplication Serial Nos. 10-2006-0001849 and 10-2006-0057693, which werefiled in the Korean Industrial Property Office on Jan. 6, 2006 and Jun.26, 2006, respectively, the entire content of each of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and an apparatus fortransmitting/receiving uplink signaling information and uplink data in aFrequency Division Multiple Access (FDMA) wireless communication systemusing a single carrier.

2. Description of the Related Art

An Orthogonal Frequency Division Multiplexing (OFDM) scheme or a SingleCarrier-Frequency Division Multiple Access (SC-FDMA) scheme similar tothe OFDM scheme have been actively researched as a scheme available forhigh speed data transmission through a wireless channel in a mobilecommunication system. An OFDM scheme, which transmits data usingmultiple carriers, is a special type of a Multiple Carrier Modulation(MCM) scheme in which a serial symbol sequence is converted intoparallel symbol sequences, and the parallel symbol sequences aremodulated with a plurality of mutually orthogonal subcarriers (orsubcarrier channels) before being transmitted.

FIG. 1 shows a transmitter of a typical OFDM system. The OFDMtransmitter includes a channel encoder 101, a modulator 102, aserial-to-parallel (S/P) converter 103, an Inverse Fast FourierTransform (IFFT) block or a Digital Fourier Transform (DFT) block 104, aparallel-to-serial (P/S) converter 105, and a Cyclic Prefix (CP)inserter 106.

The channel encoder 101 receives and channel-encodes a predeterminedinformation bit sequence. In general, a convolutional encoder, a turboencoder, or a Low Density Parity Check (LDPC) encoder is used as thechannel encoder 101. The modulator 102 modulates the channel-encoded bitsequence according to a modulation scheme, such as a Quadrature PhaseShift Keying (QPSK) scheme, an 8 PSK scheme, a 16-ary QuadratureAmplitude Modulation (16 QAM) scheme, a 64 QAM scheme, a 256 QAM scheme,etc. Meanwhile, although not shown in FIG. 1, it is obvious that a ratematching block for performing repetition and puncturing may be insertedbetween the channel encoder 101 and the modulator 102.

The S/P converter 103 receives output data from the modulator 102 andconverts the received data into parallel data. The IFFT block 104receives the parallel data output from the S/P converter 103 andperforms an IFFT operation on the parallel data. The data output fromthe IFFT block 104 is converted to serial data by the P/S converter 105.The CP inserter 106 inserts a CP into the serial data output from theP/S converter 105, thereby generating an OFDM symbol to be transmitted.

The IFFT block 104 converts the input data of the frequency domain tooutput data of the time domain. In a typical OFDM system, because inputdata is processed in the frequency domain, a Peak to Average Power Ratio(PAPR) of the data may increase when the data have been converted intothe time domain.

A PAPR is one of the most important factors to be considered in theuplink transmission. As PAPR increases, the cell coverage decreases, sosignal power required by a terminal increases. Therefore, it isnecessary to first reduce the PAPR, and it is thus possible to use anSC-FDMA scheme, which is a scheme modified from the typical OFDM scheme,for the OFDM-based uplink transmission. That is to say, it is possibleto effectively reduce the PAPR by enabling processing in the time domainwithout performing processing (channel encoding, modulation, etc.) ofdata in the frequency domain.

FIG. 2 shows a transmitter in a system employing an SC-FDMA scheme,which is a typical uplink transmission scheme. The SC-FDMA transmitterincludes a channel encoder 201, a modulator 202, a serial-to-parallel(S/P) converter 203, a Fast Fourier Transform (FFT) block 204, asub-carrier mapper 205, an IFFT block 206, a parallel-to-serial (P/S)converter 207, and a CP inserter 208.

The channel encoder 201 receives and channel-encodes a predeterminedinformation bit sequence. The modulator 202 modulates the output of thechannel encoder 201 according to a modulation scheme, such as a QPSKscheme, an 8 PSK scheme, a 16 QAM scheme, a 64 QAM scheme, a 256 QAMscheme, etc. A rate matching block may be omitted between the channelencoder 201 and the modulator 202.

The S/P converter 203 receives data output from the modulator 202 andconverts the received data into parallel data. The FFT block 204performs an FFT operation on the data output from the S/P converter 203,thereby converting the data into data of the frequency domain. Thesub-carrier mapper 205 maps the output data of the FFT block 204 to theinput of the IFFT block 206. The IFFT block 206 performs an IFFToperation on the data output from the sub-carrier mapper 205. The outputdata of the IFFT block 206 is converted to parallel data by the P/Sconverter 207. The CP inserter 208 inserts a CP into the parallel dataoutput from the P/S converter 207, thereby generating an OFDM symbol tobe transmitted.

FIG. 3 shows in more detail the structure for resource mapping shown inFIG. 2. Hereinafter, the operation of the sub-carrier mapper 205 will bedescribed with reference to FIG. 3. Data symbols 301 having beensubjected to the channel encoding and modulation are input to an FFTblock 302. The output of the FFT block 302 is input to an IFFT block304. A sub-carrier mapper 303 maps the output data of the FFT block 302to the input data of the IFFT block 304.

The sub-carrier mapper 303 maps the information symbols of the frequencydomain data converted by the FFT block 302 to corresponding input pointsor input taps of the IFFT block 304 so the information symbols can becarried by proper sub-carriers.

During the mapping procedure, when the output symbols of the FFT block302 are sequentially mapped to neighboring input points of the IFFTblock 304, the output symbols are transmitted by sub-carriers that areconsecutive in the frequency domain. This mapping scheme is called aLocalized Frequency Division Multiple Access (LFDMA) scheme.

Further, when the output symbols of the FFT block 302 are mapped toinput points of the IFFT block 304 having a predetermined intervalbetween them, the output symbols are transmitted by sub-carriers havingequal intervals between them in the frequency domain. This mappingscheme is called either an Interleaved Frequency Division MultipleAccess (IFDMA) scheme or a Distributed Frequency Division MultipleAccess (DFDMA) scheme.

Although FIGS. 2 and 3 show one method of implementing the SC-FDMAtechnology in the frequency domain, it is also possible to use variousother methods, such as a method of implementing the technology in thetime domain.

Diagrams (a) and (b) in FIG. 4 are views for comparison between thepositions of sub-carriers used for the DFDMA and the LFDMA in thefrequency domain. In diagram (a), the transmission symbols of a terminalusing the DFDMA scheme are distributed with equal intervals over theentire frequency domain (that is, the system band). In diagram (b), thetransmission symbols of a terminal using the LFDMA scheme areconsecutively located at some part of the frequency domain.

According to the LFDMA scheme, because consecutive parts of the entirefrequency band are used, it is possible to obtain a frequency schedulinggain by selecting a partial frequency band having good channel gain inthe frequency selective channel environment in which severe channelchange of frequency bands occurs. In contrast, according to the DFDMAscheme, it is possible to obtain a frequency diversity gain astransmission symbols have various channel gains by using a large numberof sub-carriers distributed over a wide frequency band.

In order to maintain a characteristic of a single carrier as describedabove, simultaneously transmitted information symbols should be mappedto the IFFT block so they can always satisfy the LFDMA or DFDMA afterpassing through a single FFT block (or DFT block).

In an actual communication system, various information symbols may betransmitted. For example, in the uplink of a Long Term Evolution (LTE)system using the SC-FDMA based on a Universal Mobile TelecommunicationsSystem (UMTS), uplink data, control information regulating a transportscheme of the uplink data (which includes Transport Format (TF)information of the uplink data and/or Hybrid Automatic Repeat reQuest(HARQ) information), an ACKnowledgement/Negative ACKnowledgment(ACK/NACK) for a HARQ operation for downlink data, a Channel QualityIndication (CQI) indicating the channel status reported to be used forscheduling of a base station, etc. may be transmitted. Those enumeratedinformation items have different transmission characteristics,respectively.

Uplink data can be transmitted in a situation in which a terminal hasdata in a transmission buffer of the terminal and has receivedpermission for uplink transmission from a base station. The controlinformation regulating the transport scheme of the uplink data istransmitted only when the uplink data is transmitted. Sometimes, uplinkdata may be transmitted without transmission of control information. Incontrast, the ACK/NACK, which is transmitted in response to downlinkdata, has no relation to transmission of uplink data. That is, eitherboth the uplink data and the ACK/NACK may be simultaneously transmittedor only one of them may be transmitted. Further, the CQI, which istransmitted at a given time, also has no relation to transmission ofuplink data. That is, either both the uplink data and the CQI may besimultaneously transmitted or only one of them may be transmitted.

As described above, various types of uplink information are transmittedin the SC-FDMA system. Under the restriction of use of a single FFTblock, which is a characteristic of a single sub-carrier, it isnecessary to effectively control transmission of information in order totransmit various types of information as described above. That is tosay, it is necessary to arrange a specific transmission rule when onlyuplink data is transmitted, when only an ACK/NACK or a CQI istransmitted, and when both uplink data and uplink signaling information(ACK/NACK or CQI) are transmitted.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve theabove-mentioned problems occurring in the prior art, and provides amethod and an apparatus for transmitting uplink information items havingvarious characteristics by using a single FFT block.

The present invention also provides a method and an apparatus fortransmitting uplink signaling information, such as ACK/NACK or CQI,according to existence or absence of uplink data.

The present invention also provides a method and an apparatus forindicating whether the uplink signaling information, such as ACK/NACK orCQI, uses resources allocated to uplink data in transmission of theuplink data.

In accordance with an aspect of the present invention, there is provideda method for transmitting uplink information in a Single CarrierFrequency Division Multiple Access (SC-FDMA) wireless communicationsystem. The method includes determining whether Acknowledgement/NegativeAcknowledgement (ACK/NACK) information indicating whether or notdownlink data has been received exists to be transmitted, if uplink dataexists to be transmitted; multiplexing the uplink data and controlinformation for the uplink data and transmitting multiplexed dataincluding the uplink data and the control information, through afrequency resource allocated for the uplink data, if no ACK/NACKinformation exists; and multiplexing the uplink data, the controlinformation for the uplink data, and the ACK/NACK information, andtransmitting multiplexed data through the frequency resource allocatedfor the uplink data, if the ACK/NACK information exists. The ACK/NACKinformation is located adjacent to a pilot for the uplink data.

In accordance with another aspect of the present invention, there isprovided a terminal for transmitting uplink information in a SingleCarrier Frequency Division Multiple Access (SC-FDMA) wirelesscommunication system. The terminal includes a multiplexer formultiplexing uplink data and control information for the uplink data, ifuplink data exists to be transmitted and no Acknowledgement/NegativeAcknowledgement (ACK/NACK) information is to be transmitted, andmultiplexing the uplink data, the control information for the uplinkdata, and the ACK/NACK information if both the uplink data exists to betransmitted and the ACK/NACK information exists to be transmitted; and adata resource mapper for transmitting information multiplexed by themultiplexer through a frequency resource allocated for the uplink data.The ACK/NACK information indicates whether or not downlink data has beenreceived, and the ACK/NACK information is located adjacent to a pilotfor the uplink data.

In accordance with another aspect of the present invention, there isprovided a method for receiving uplink information in a Single CarrierFrequency Division Multiple Access (SC-FDMA) wireless communicationsystem. The method includes receiving multiplexed data including uplinkdata, a pilot, and Acknowledgement/Negative Acknowledgement (ACK/NACK)information from a terminal; and demultiplexing the multiplexed dataincluding the uplink data, the pilot, and the ACK/NACK informationindicating whether or not the terminal has received downlink data. TheACK/NACK information is located adjacent to both sides of the pilot forthe uplink data, and the pilot is used for demodulation of the uplinkdata.

In accordance with another aspect of the present invention, there isprovided a base station for receiving uplink information in a SingleCarrier Frequency Division Multiple Access (SC-FDMA) wirelesscommunication system. The base station includes a receiver for receivingmultiplexed data including uplink data, a pilot, andAcknowledgement/Negative Acknowledgement (ACK/NACK) information from aterminal; and a controller for controlling an operation ofdemultiplexing the multiplexed data including the uplink data, thepilot, and the ACK/NACK information indicating whether or not theterminal has received downlink data. The ACK/NACK information is locatedadjacent to both sides of the pilot for the uplink data, and the pilotis used for demodulation of the uplink data.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating a structure of a transmitter of atypical OFDM system;

FIG. 2 is a block diagram illustrating a structure of a transmitter in asystem employing an SC-FDMA scheme, which is a typical uplinktransmission scheme;

FIG. 3 is a block diagram illustrating in more detail the structure forresource mapping shown in FIG. 2;

FIG. 4 illustrates views for comparison between the positions ofsub-carriers used for the DFDMA and the LFDMA in the frequency domain;

FIG. 5 illustrates structures of an uplink transmission frame and itssub-frame of an LTE system according to the present invention;

FIG. 6 illustrates the sub-frame 502 of FIG. 5 on the time domain andthe frequency domain according to the present invention;

FIG. 7 illustrates the resources allocated to uplink data and ACK/NACKaccording to the present invention;

FIG. 8 illustrates use of frequency-time resources according to thefirst embodiment of the present invention;

FIG. 9 is a flow diagram of an operation of a transmitter according tothe first embodiment of the present invention;

FIG. 10 is a block diagram illustrating the structure of the transmitteraccording to the first embodiment of the present invention;

FIG. 11 is a flow diagram of an operation of a receiver according to thefirst embodiment of the present invention;

FIG. 12 is a block diagram illustrating the structure of the receiveraccording to the first embodiment of the present invention;

FIG. 13 is a flow diagram of an operation of a transmitter according tothe second embodiment of the present invention;

FIG. 14 is a block diagram illustrating the structure of the transmitteraccording to the second embodiment of the present invention;

FIG. 15 is a flow diagram of an operation of a receiver according to thesecond embodiment of the present invention;

FIG. 16 is a block diagram illustrating the structure of the receiveraccording to the second embodiment of the present invention;

FIG. 17 illustrates a sub-frame according to the third embodiment of thepresent invention in which the ACK/NACK and the CQI are multiplexed atthe same time;

FIG. 18 illustrates use of frequency-time resources according to thethird embodiment of the present invention;

FIG. 19 illustrates a structure of CQI information according to thethird embodiment of the present invention;

FIG. 20 is a flow diagram of an operation of a transmitter according tothe third embodiment of the present invention; and

FIG. 21 is a flow diagram of an operation of a receiver according to thethird embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Hereinafter, various embodiments of the present invention will bedescribed with reference to the accompanying drawings. In the followingdescription, a detailed description of known functions andconfigurations incorporated herein will be omitted when it may make thesubject matter of the present invention rather unclear. Further, in thefollowing description of the present invention, various specificdefinitions are provided only to help general understanding of thepresent invention, and it is apparent to those skilled in the art thatthe present invention can be implemented without such definitions.

The present invention multiplexes different types of uplink informationto enable transmission of the uplink information, which can satisfy asingle carrier characteristic in a wireless communication system using aSingle Carrier Frequency Division Multiple Access (SC-FDMA) scheme. Thefollowing description discusses multiplexing for uplink transmission ofuplink data, control information, Acknowledgement/NegativeACKnowledgement (ACK/NACK), Channel Quality Indication (CQI), etc. in anSC-FDMA wireless communication system. As used herein, the otherinformation except for the uplink data and control information thereof,that is, information including ACK/NACK and CQI, is referred to as“uplink signaling information.”

A Long Term Evolution (LTE) system, which is being standardized by the3^(rd) Generation Partnership Project (3GPP), is discussed in order todescribe the present invention. The LTE system employs a SC-FDMA schemefor uplink transmission. FIG. 5 shows an uplink transmission frame andits sub-frame according to the present invention.

In FIG. 5, reference numeral 501 denotes a radio frame, which is anuplink transmission unit and is defined to have a length of 10 ms. Oneradio frame 501 includes 20 sub-frames 502, each of which has a lengthof 0.5 ms. Further, each sub-frame 502 includes six Long Blocks (LBs)503, 505, 506, 507, 508, and 510, two Short Blocks (SBs) 504 and 509,and CPs 511 and 512 located before the blocks one before one. The LBs503 to 510 carry information except for pilots used as a reference forcoherent modulation, and SBs 504 and 509 are used to carry the pilots.

FIG. 6 shows the sub-frame 502 of FIG. 5 on the time domain and thefrequency domain according to the present invention. The horizontal axisindicates the frequency domain 601 and the vertical axis indicates thetime domain 602. The range of the frequency domain 601 corresponds tothe entire frequency band 604 and the range of the time domain 602corresponds to one sub-frame 603. As noted, the SBs 605 and 607 carrypilots, and the LBs 607 and 608 carry other information except for thepilots. As described above, uplink data transmitted according toresource allocation by a base station, control information in relationto the uplink data, ACK/NACK for indicating success or failure inreception of downlink data, CQI for indicating a channel status, etc.are transmitted by using the uplink resource.

A determination to transmit the uplink data is made according toscheduling of a base station, and a determination of a resource to beused is also made according to allocation by the base station. Thecontrol information transmitted together with the uplink data is alsotransmitted according to the resources allocated by the base station. Incontrast, since the ACK/NACK is generated based on downlink data, theACK/NACK is transmitted using an uplink resource automatically allocatedaccording to whether the downlink data is transmitted, in response tothe control channel defining the downlink data or the downlink datachannel. Further, since it is usual that the CQI is periodicallytransmitted, the CQI is transmitted using a resource determined inadvance through setup by higher signaling.

Because the information items use a variety of resource allocationmethods as described above, the variety of resource allocation methodsare simultaneously used when various types of information aretransmitted together. In order to satisfy a characteristic of a singlesub-carrier, the resource used during one sub-frame must necessarilymaintain a characteristic of the LFDMA or DFDMA. For example, whenuplink data and ACK/NACK are transmitted simultaneously, that is, duringone Transmission Time Interval (TTI), the uplink data uses the resourceallocated by the base station, and the ACK/NACK uses a resourcedetermined by another method, for example, a resource determinedaccording to a control channel for downlink data. Therefore, use of thetwo resources may cause a contradiction to a characteristic of a singlesub-carrier, thereby increasing the PAPR. Therefore, the presentinvention provides a method by which simultaneously transmittedinformation items can always maintain a characteristic of a singlesub-carrier.

Specifically, transmission of uplink data and ACK/NACK together will bedescribed hereinafter. The transmission of uplink data may beaccompanied with transmission of control information of the uplink data.Further, the discussion below may also be applied to other uplinksignaling information, such as the CQI instead of the ACK/NACK.

In order to always maintain a characteristic of a single sub-carriereither when only one of the ACK/NACK and the uplink data is transmittedor when both of them are simultaneously transmitted, the presentinvention provides the following method. That is, when only one of theACK/NACK and the uplink data is transmitted, a resource allocated to thecorresponding information is used. Specifically, when only the uplinkdata is transmitted, the uplink data is transmitted by using theresource allocated by the base station. When only the ACK/NACK istransmitted, the ACK/NACK is transmitted by using the resourcedetermined for the transmission of the ACK/NACK. However, when both ofthe ACK/NACK and the uplink data are simultaneously transmitted, theACK/NACK and the uplink data are transmitted by using only the resourceallocated for the uplink data, and the resource determined for thetransmission of the ACK/NACK is disregarded. In other words, theACK/NACK and the uplink data are simultaneously transmitted by using theresource allocated for the uplink data.

FIG. 7 shows resources allocated to uplink data and ACK/NACK accordingto the present invention. Reference numeral 701 denotes a frequencydomain and reference numeral 702 denotes a time domain. Further, withinone time interval, sub-carriers allocated to data corresponds to a firstresource 703 and sub-carriers allocated to the ACK/NACK corresponds to asecond resource 704. The resources 703 and 704 allocated to the uplinkdata and the ACK/NACK as described above are separated on the frequencydomain. Although FIG. 7 shows logical separation between the resources703 and 704 allocated to the uplink data and the ACK/NACK, the resources703 and 704 are separated into two sub-carrier sets not only when theLFDMA is used but also when the DFDMA is used.

When the entire frequency resources have been divided into twosub-carrier sets, uplink data is transmitted by using a first resource703 when there exists only the uplink data, while ACK/NACK istransmitted by using a second resource 704 when only the ACK/NACKexists. In contrast, when both the uplink data and the ACK/NACK exist,both the uplink data and the ACK/NACK are multiplexed and transmitted byusing only the first resource 703 without using the second resource 704.

That is, the transmission point of the ACK/NACK changes according towhether uplink data exists. In transmitting the uplink data, thequantity of information is different and the transport format of theuplink data is thus different according to whether the ACK/NACK exists.Therefore, the type and quantity of information to be transmitted shouldbe promised in advance between the base station and the terminal.

When the terminal transmits only the uplink data and the base stationmisunderstands that the terminal has transmitted both the uplink dataand the

ACK/NACK, it is impossible to expect a normal communication becauseencoding and decoding are performed according to differentencoding/decoding schemes. For example, such a communication error mayoccur when the terminal has successfully received scheduling informationfor the uplink data but has failed to receive downlink data, anddetermines that there is no downlink data without sending an ACK/NACK.

Therefore, it is necessary for the base station to exactly understandthe type and quantity of information transmitted by the terminal Forexample, the base station determines the type of the informationreceived from the terminal either by analyzing the informationtransmitted by the terminal or according to whether the base station hastransmitted downlink data to the terminal. For another example, theterminal may clearly report the type of uplink information to the basestation.

First Embodiment

According to the first embodiment of the present invention, the terminalmay inform the base station whether the uplink signaling information(specifically, the ACK/NACK) will be transmitted. Hereinafter, use offrequency-time resources according to the first embodiment of thepresent invention will be described with reference to FIG. 8.

In FIG. 8, reference numeral 801 denotes one sub-frame used in theuplink of an LTE system, and reference numeral 808 denotes the frequencyband allocated for transmission of data. In the frequency band 808,reference numeral 802 denotes a first sub-carrier set allocated to afirst terminal that transmits uplink data without ACK/NACK, andreference numeral 803 denotes a second sub-carrier set allocated to asecond terminal that transmits uplink data together with ACK/NACK.

In the first sub-carrier set 802, pilots 804 and 806 for channelestimation are transmitted through the allocated time resource. Pilots804 and 806 have a sequence with a pilot pattern known to the basestation and the terminal, representatives of which includes an all 1sequence (all bits of which have a value of 1). That is, pilots 804 and806 for sub-carrier set 802 without ACK/NACK are set to have arepresentative sequence such as an all 1 sequence. In contrast, pilots805 and 807 for the second sub-carrier set 803 carrying the ACK/NACK areset to have a sequence different from that of pilots 804 and 806. Thatis, sub-carrier set 803 uses a pilot other than the all 1 sequence. Forexample, it uses a pilot having a sequence in which 1 and −1 arealternately repeated. At this time, by setting the minimum distancebetween the two different sequences to be largest, it is possible tominimize the probability of error in discriminating between the twosequences by the base station.

In brief, the terminal informs the base station through pilots havingsequences of different pilot patterns of whether the ACK/NACK issimultaneously transmitted together with uplink data.

FIG. 9 shows an operation of a transmitter (terminal) according to thefirst embodiment of the present invention, and FIG. 10 shows thetransmitter (terminal). Referring to FIG. 9, when the operation of theterminal has started, the terminal determines whether data to betransmitted exists in step 902. When data exists to be transmitted bythe terminal, the terminal is instructed through scheduling of the basestation, etc. When the determination in step 902 concludes that dataexists to be transmitted and the base station has allocated a resourcefor transmission of the data, the terminal determines whether ACK/NACKexists to be transmitted (step 903). When ACK/NACK exists to betransmitted the information is determined through an HARQ operation fordownlink data and based on whether the downlink data has been received.

When it has been determined in step 903 that there is ACK/NACK to betransmitted, the terminal sets pilot pattern #2 having a predeterminedsequence as a pilot signal for the data and multiplexes the data, theACK/NACK, and control information for the data in step 905. Then, instep 908, the terminal maps the multiplexed information to the dataresource allocated by the base station, as described above, and thentransmits the mapped information. At this time, the pilot signal ofpilot pattern #2 is also transmitted through short blocks, which arepredetermined time resources of the data resources.

In contrast, when it has been determined in step 903 that no ACK/NACK isto be transmitted, the terminal sets pilot pattern #1 having apredetermined sequence as a pilot signal for the data and multiplexesthe data and control information for the data in step 906. Then, in step909, the terminal maps the multiplexed information to the data resourceallocated by the base station as described above and then transmits themapped information. At this time, the pilot signal of pilot pattern #1is also transmitted through short blocks, which are predetermined timeresources of the data resources. Steps 905 and 906 may be omitted whenthe terminal does not clearly inform the base station whether theterminal will transmit ACK/NACK.

Meanwhile, when the determination in step 902 concludes that no uplinkdata is to be transmitted, the terminal determines whether ACK/NACKexists to be transmitted in step 904. When ACK/NACK exists to betransmitted, the terminal transmits the ACK/NACK by using a resourceallocated for the ACK/NACK, that is, by using an ACK/NACK resourcecorresponding to the resource of the downlink data in step 907. Incontrast, when no ACK/NACK is to be transmitted, the process isterminated.

Referring to the transmitter shown in FIG. 10, ACK/NACK 1001 fordownlink data is subjected to an encoding, such as a repetition codingby a channel encoder 1006, and is then input to a demultiplexer (DEMUX)1016. The output path from the DEMUX 1016 depends on a signal 104indicating whether uplink data 1002 exists. Specifically, the DEMUX 1016is connected to output to path 1009 when uplink data 1002 exists.Otherwise, the DEMUX 1016 is connected to output path 1008.

The uplink data 1002 is encoded by a channel encoder 1013 and is theninput to a multiplexer 1015, while the control information 1003indicating the transport format of the uplink data 1002 is encoded by achannel encoder 1014, and is then input to the multiplexer 1015.Further, the encoded ACK/NACK may be input to the multiplexer 1015through output path 1009. One of the pilot signals 1011 and 1012 for theresource (data resource) allocated for the uplink data 1002 is inputthrough the switch 1012 to the multiplexer 1015. The selection by theswitch 1012 depends on a signal 105 indicating whether ACK/NACK exists.Specifically, the switch 1012 selects the pilot signal 1011 of pilotpattern #1 when the ACK/NACK is not transmitted to the data resource,and selects the pilot signal 1012 of pilot pattern #2 when the ACK/NACKis transmitted to the data resource.

The information multiplexed by the multiplexer 1015 is mapped to thedata resource by a data resource mapper 1021 and is then transmitted.The data resource mapper 1021 includes an FFT (or DFT) block, asub-carrier mapper, and an IFFT block as described above with referenceto FIG. 2. That is, when both the uplink data 1002 and the ACK/NACK 1001exist, the uplink data 1002 and the ACK/NACK 1001 are multiplexed beforethe FFT operation. In contrast, when no uplink data exists, the encodedACK/NACK output through output path 1008 is mapped to a resource(ACK/NACK resource) appointed for the ACK/NACK by an ACK/NACK resourcemapper 1020 and is then transmitted.

FIG. 11 shows an operation of a receiver (base station) according to thefirst embodiment of the present invention, and FIG. 12 shows thereceiver (base station). Referring to FIG. 11, when the operation of thebase station has started, the base station determines whether it willreceive data from the terminal in step 1102. The determination is madeas to whether the base station will receive data from the terminal basedon whether the base station has allocated a data resource for uplink tothe terminal When the determination in step 1102 concludes that dataexists to be received, the base station receives information through aresource allocated for the data, that is, through the data resource instep 1103, and determines the pattern of the pilot signal included inthe data resource in step 1105.

In step 1105, the base station determines the pilot pattern of the pilotsignal by correlating the pilot signal with pilot pattern #1 and pilot#2, which are already known, by using a correlator, etc. When the pilotsignal has pilot pattern #1, the base station determines that the dataresource does not include ACK/NACK, and acquires the uplink data andcontrol information through demultiplexing and decoding of the receivedinformation. In contrast, when the pilot signal has pilot pattern #2,the base station determines that the data resource includes ACK/NACK,and acquires the uplink data, control information, and ACK/NACK throughdemultiplexing and decoding of the received information. When theterminal does not clearly inform the base station of whether to transmitACK/NACK, the base station may determine whether it will receiveACK/NACK, according to whether a downlink scheduler has previouslyallocated the resource for the downlink data, instead of using the pilotpattern of the pilot signal in step 1105.

When the determination in step 1102 concludes that no data is to bereceived, the base station determines in step 1104 whether ACK/NACKexists to be received, based on whether a downlink scheduler haspreviously allocated the resource for the downlink data. When ACK/NACKexists to be received, the base station receives information through theresource (ACK/NACK resource) allocated for ACK/NACK in step 1106, andacquires ACK/NACK by decoding the received information in step 1109.When the determination in step 1104 concludes that no ACK/NACK is to bereceived, the process is terminated.

Referring to FIG. 12, the base station receives a radio signal through areceiver block 1201. Then, a demultiplexer (DEMUX) 1202 demultiplexesthe radio signal and then extracts a signal for a specific terminal. Atthis time, the DEMUX 1202 operates by using a control signal of ascheduler 1215. That is, when a data resource has been allocated to theterminal by the scheduler 1215, the DEMUX 1202 outputs only the dataresource information 1204 in the extracted signal. In contrast, whenreceiving the ACK/NACK without data, the DEMUX 1202 outputs only theACK/NACK resource information 1212 in the extracted signal. A channeldecoder 1213 decodes the ACK/NACK resource information 1212 and outputsthe decoded ACK/NACK.

The data resource information 1204 is provided to a pilot determinationblock 1203 and a demultiplexer (DEMUX) 1205. The pilot determinationblock 1203 determines the pilot pattern of the pilot signal included inthe data resource information 1204, and makes a determination based onthe pilot pattern whether the ACK/NACK exists. Based on a result of thedetermination, a control signal 1216 indicating existence or absence ofthe ACK/NACK is input to the DEMUX 1205. When the control signal 1216indicates that the ACK/NACK exists, the DEMUX 1205 demultiplexes thedemultiplexed information 1204 again into encoded uplink data 1222,encoded control information 1221, and encoded ACK/NACK 1223. The outputs1221, 1222, and 1223 of the DEMUX 1205 are decoded by the channeldecoders 1206, 1207, and 1208 and are then output as uplink data 1210,control information 1209, and ACK/NACK 1211.

In contrast, when the control signal 1216 indicates that no ACK/NACKexists, the DEMUX 1205 demultiplexes the demultiplexed information 1204again into encoded uplink data 1222 and encoded control information1221. The outputs 1221 and 1222 of the DEMUX 1205 are decoded by thechannel decoders 1206 and 1207 and are then output as uplink data 1210and control information 1209. At this time, the channel decoder 1208 forthe ACK/NACK 1211 does not operate.

Second Embodiment

According to the second embodiment of the present invention, an ACK/NACKfield of one bit or multiple bits is arranged within controlinformation. When ACK/NACK is transmitted together with uplink data, theACK/NACK is carried by the ACK/NACK field predefined in the controlinformation. Therefore, only the encoded data and encoded controlinformation are multiplexed before resource mapping. The ACK/NACK fieldis set to have a value indicating ACK or NACK according to success orfailure in reception of downlink data when ACK/NACK exists. Otherwise,the ACK/NACK field is set to have a value indicating or the NACK.

FIG. 13 shows an operation of a transmitter (terminal) according to thesecond embodiment of the present invention, and FIG. 14 shows thetransmitter (terminal).

Referring to FIG. 13, when the operation of the terminal has started,the terminal determines whether data exists to be transmitted in step1302. When data exists to be transmitted by the terminal, the terminalis instructed through scheduling of the base station, etc. When thedetermination in step 1302 concludes that data exists to be transmittedand the base station has allocated a resource for transmission of thedata, the terminal determines whether ACK/NACK exists to be transmittedin step 1303. The determination of whether ACK/NACK exists to betransmitted is performed through an HARQ operation for downlink data,and is based on whether the downlink data has been received.

When it has been determined in step 1303 that there is ACK/NACK to betransmitted, the terminal sets ACK/NACK in the ACK/NACK field of controlinformation and multiplexes the data and control information in step1305. Then, in step 1308, the terminal maps the multiplexed informationto the data resource and then transmits the mapped information. Incontrast, when it has been determined in step 1303 that no ACK/NACK isto be transmitted, the terminal sets NACK in the ACK/NACK field ofcontrol information and multiplexes the data and control information instep 1307. Then, in step 1308, the terminal maps the multiplexedinformation to the data resource and then transmits the mappedinformation.

Meanwhile, when the determination in step 1302 concludes that no uplinkdata is to be transmitted, the terminal determines whether ACK/NACKexists to be transmitted in step 1304. When ACK/NACK exists to betransmitted, the terminal transmits the ACK/NACK by using a resourceallocated for the ACK/NACK, that is, by using the ACK/NACK resource instep 1309. In contrast, when no ACK/NACK is to be transmitted, theprocess is terminated.

Referring to the transmitter shown in FIG. 14, the uplink data 1401 isencoded by a channel encoder 1408 and is then input to a multiplexer(MUX) 1411. In contrast, the ACK/NACK 1402 indicating success or failurein reception of downlink data is transferred through a demultiplexer(DEMUX) 1415 to output path 1417 or output path 1416 according to thecontrol signal 1420 indicating existence or absence of the uplink data1401. When the uplink data 1401 is not transmitted, the ACK/NACK 1402transferred to output path 1416 is subjected to encoding, such asrepetition encoding by a channel encoder 1406, and is then transmittedusing an ACK/NACK resource by an ACK/NACK resource mapper 1410.

When the uplink data 1401 is not transmitted, the ACK/NACK 1402transferred to output path 1417 is input to the switch 1405. The switch1405 selects between a predetermined NACK 1404 and the ACK/NACK 1402.Specifically, the switch 1405 selects the ACK/NACK 1402 when theACK/NACK 1402 exists in output path 1417, and selects the NACK 1404 whenthe ACK/NACK 1402 does not exist in output path 1417.

The output of the switch 1405 is multiplexed with control information1403 by a MUX 1409, and the multiplexed information is encoded by achannel encoder 1407 and is then input to the multiplexer (MUX) 1411.The MUX 1411 multiplexes the data encoded by the channel encoder 1408and the control information encoded by the channel encoder 1407, and themultiplexed information is then transmitted using the data resource by adata resource mapper 1412.

In the transmitter as described above, when uplink data exists, theACK/NACK is encoded and transmitted together with control information.At this time, the control information including the ACK/NACK uses asuperior decoding performance than the control information that does notinclude the ACK/NACK. This is because an error requirement of thecontrol information is usually lower than an error requirement of theACK/NACK. In the structure shown in FIG. 14, the control information andthe ACK/NACK are simultaneously encoded by one channel encoder 1407, andthe channel encoder 1407 operates in accordance with the lower errorrequirement of the ACK/NACK.

When the channel encoding scheme of the control information includingthe ACK/NACK has a characteristic of unequal error protection,information bits input to the channel encoder 1407 have different errorprobabilities according to their positions. Therefore, by locating theACK/NACK field at a position capable of minimizing the error probabilitywithin the control information, it is possible to satisfy both the errorrequirement of the ACK/NACK and the error requirement of the controlinformation. For example, section 4.7.1.2 of 3GPP TS 25.212 v6.6.0describes a channel encoding scheme having an unequal error protectionproperty which can cause the Most Significant Bit (MSB) to have thelowest error probability. Therefore, when the described channel encodingscheme is used, it is possible to lower the error probability of theACK/NACK and to properly maintain the error probability of the controlinformation by setting the ACK/NACK field as the MSB within the controlinformation and by using proper transmission power.

FIG. 15 shows an operation of a receiver (base station) according to thesecond embodiment of the present invention, and FIG. 16 shows thereceiver (base station). Referring to FIG. 15, when the operation of thebase station has started, the base station determines whether the basestation will receive data from the terminal in step 1502. Thedetermination of whether the base station will receive data from theterminal is based on whether the base station has allocated a dataresource for uplink to the terminal. When the determination in step 1502concludes that data exists to be received, the base station receivesinformation through a resource allocated for the data, that is, throughthe data resource in step 1503, decodes control information included inthe data resource in step 1504, and obtains the ACK/NACK by reading theACK/NACK field included in the control information in step 1505.

In contrast, when the determination in step 1502 concludes that no datais to be received, the base station determines in step 1506 whetherACK/NACK exists to be received. When ACK/NACK exists to be received, thebase station receives information through the resource (ACK/NACKresource) allocated for the ACK/NACK in step 1507, and acquires ACK/NACKby decoding the received information in step 1508. When thedetermination in step 1506 concludes that no ACK/NACK is to be received,the process is terminated.

Referring to FIG. 16, the base station receives a radio signal through areceiver block 1601. Then, a demultiplexer (DEMUX) 1602 demultiplexesthe radio signal and then extracts a signal for a specific terminal. Atthis time, the DEMUX 1602 operates by using a control signal of a basestation scheduler 1603. That is, when a data resource has been allocatedto the terminal by the scheduler 1603, the DEMUX 1602 outputs only thedata resource information 1604 in the extracted signal. In contrast,when receiving the ACK/NACK without data, the DEMUX 1602 outputs onlythe ACK/NACK resource information 1605 in the extracted signal. Achannel decoder 1613 decodes the ACK/NACK resource information 1605 andoutputs the decoded ACK/NACK 1614.

The data resource information 1604 is demultiplexed into encoded dataand encoded control information by a demultiplexer 1606. A channeldecoder 1607 obtains the uplink data 1609 by decoding the encoded data.Further, a channel decoder 1608 decodes the encoded control information,and a demultiplexer 1610 demultiplexes the decoded information andseparately outputs pure control information 1611 and the ACK/NACK 1612.

Third Embodiment

Hereinafter, a third embodiment of the present invention will bedescribed for a case where the ACK/NACK and the CQI, which are uplinksignaling information of uplink data to be transmitted, are multiplexedat the same time, and the uplink data is transmitted at a separate timefrom that for the uplink signaling information.

FIG. 17 shows a sub-frame according to the third embodiment of thepresent invention in which the ACK/NACK and the CQI are multiplexed atthe same time. One sub-frame 1708 includes five long blocks LB#1˜LB#5,four short locks SB#1, SB#2, SB#3, SB#4, and CPs 511 and 512 locatedbefore the blocks one before one. In comparison with the sub-frame shownin FIG. 5, one long block 503 is replaced by two short blocks SB#1, SB#21700 and 1702 in the sub-frame shown in FIG. 17.

For example, SB#1 1700 carries ACK/NACK and CQI, and SB#2 1702 carries apilot used in order to demodulate the ACK/NACK and CQI. Further, theother blocks 1706 carry uplink data, control information, and otherinformation. A pilot used for demodulation of the uplink data can betransmitted through SB#3 or SB#4.

FIG. 18 shows an example of mapping of the ACK/NACK and the CQI in thefrequency domain, which are carried by SB#1 1800 and SB#2 1802 in thesub-frame shown in FIG. 17. In FIG. 18, the horizontal axis indicateslogical mapping of frequency resources 1808. As shown, N number ofACK/NACK channels (ACKCHs) 1804 and K number of CQI channels (CQICHs)1806 are allocated to the frequency resources of SB#1 1800. According tothe applied transmission scheme from among the IFDMA scheme and theLFDMA scheme, the ACK and CQI channels may use a sub-carrier setincluding discontinuous sub-carriers 401 or continuous sub-carriers 402in the physical frequency domain as shown in FIG. 4. In order totransmit the ACK/NACK and/or the CQI, a corresponding terminalmultiplexes the ACK/NACK and/or the CQI by using an ACK/NACK channeland/or a CQI channel allocated within a corresponding sub-frame (thatis, at the same time).

Therefore, when a terminal simultaneously transmits the ACK/NACK and theCQI, the CQI information transmitted through the CQI channel may have astructure as shown in FIG. 19, in order to enable the ACK/NACK and theCQI to be transmitted by a single sub-carrier.

FIG. 19 shows a structure of CQI information according to the thirdembodiment of the present invention. Reference numeral 1900 denotes aCQI field, and reference numeral 1902 denotes an ACK/NACK field.Although the ACK/NACK field is expressed to have a size of 1 bit in FIG.19, the ACK/NACK field may have a size of multiple bits according to amethod of expressing the ACK/NACK and the HARQ transmission scheme, etc.

FIG. 20 shows a process for transmitting ACK/NACK and CQI by atransmitter (terminal) according to the third embodiment of the presentinvention. Upon starting to operate, the terminal determines whether itis the time to transmit CQI (step 2002). The time to transmit CQI isdetermined, for example, by a specific short block allocated for a CQIchannel within a periodically determined specific sub-frame. When it isthe time to transmit CQI, the terminal proceeds to step 2003 in whichthe terminal determines whether ACK/NACK exists to be transmitted.

When the determination in step 2003 concludes that it is necessary tosimultaneously transmit both the CQI and the ACK/NACK, the terminal setsa value of ACK/NACK in the ACK/NACK field within the CQI information andsets a CQI value in the CQI field in step 2010. Then, the terminalproceeds to step 2014, in which the terminal channel-encodes both theCQI field and the ACK/NACK field and performs single-carriertransmission through a frequency-time resource (hereinafter, referred toas “CQI resource”) allocated to the CQI channel.

When the determination in step 2003 concludes that no ACK/NACK is to betransmitted or it is not the time to transmit the ACK/NACK, the terminalsets NACK in the ACK/NACK field within the CQI information and sets aCQI value in the CQI field in step 2012. Then, the terminal proceeds tostep 2014, in which the terminal channel-encodes the CQI informationincluding both the CQI field and the ACK/NACK field and performs thesingle-carrier transmission.

Meanwhile, when the determination in step 2002 concludes that it is notthe time to transmit CQI, the terminal determines whether ACK/NACKexists to be transmitted in step 2004. When ACK/NACK exists to betransmitted and it is the time to transmit the ACK/NACK, the terminalsets a value of ACK/NACK in the ACK/NACK information to be transmittedthrough the ACK/NACK channel in step 2018. Then, in step 2020, theterminal encodes the ACK/NACK information and then performssingle-carrier transmission through a frequency-time resource(hereinafter, referred to as “ACK/NACK resource”) allocated to the ACKchannel. When the determination in step 2004 concludes that no ACK/NACKis to be transmitted, the process is terminated.

FIG. 21 shows an operation of a receiver (base station) according to thethird embodiment of the present invention.

According to the third embodiment of the present invention, when onlythe CQI without the ACK/NACK is transmitted, the ACK/NACK field withinthe CQI information is set as NACK. Therefore, the receiver (basestation) can improve the decoding performance of the CQI decoding bysetting the NACK value with a value which the receiver has alreadyknown. This method can be also applied when decoding the controlinformation according to the second embodiment of the present invention.

Upon starting to operate, the terminal determines whether it is the timeto receive CQI information from the terminal in step 2102. When it isthe time to receive CQI information from the terminal, the base stationproceeds to step 2103 in which the base station receives the CQIinformation through a CQI resource. Then, in step 2105, the base stationdetermines whether ACK/NACK exists to be received. Then, when ACK/NACKexists to be received and it is the time to receive the ACK/NACK, thebase station proceeds to step 2107 in which the base station decodes theCQI field and the ACK/NACK field included in the CQI information. Then,in step 2109, the base station determines the ACK/NACK and the CQI.

In contrast, when no ACK/NACK is to be received or it is not the time toreceive the ACK/NACK, the base station sets a field value of NACK in theACK/NACK field within the CQI information in step 2112. Then, in step2114, the base station decodes the CQI field included in the CQIinformation, thereby determining the CQI. In step 2112, the base stationmay forcibly set the field value of NACK in the ACK/NACK field.

Meanwhile, when the determination in step 2102 concludes that it is notthe time to receive the CQI information, the base station determineswhether ACK/NACK exists to be received in step 2104. When ACK/NACKexists to be received and it is the time to receive the ACK/NACK, thebase station receives the ACK/NACK information through a resourceallocated for the ACK/NACK channel, that is, through the ACK/NACKresource in step 2120. Then, in step 2122, the base station decodes thereceived ACK/NACK, thereby acquiring the ACK/NACK. When thedetermination in step 2104 concludes that no ACK/NACK is to be received,the process is terminated.

The present invention presents a scheme for multiplexing and resourcemapping of uplink data and uplink signaling information, in order tosatisfy the single sub-carrier characteristic in the transmission of theuplink data and uplink signaling information in an SC-FDMA wirelesscommunication system. The present invention can eliminate factorsdisturbing the single carrier transmission and prevent PAPR increase,which may occur when uplink data occurring according to determination ofa scheduler, ACK/NACK occurring according to transmission of downlinkdata, and uplink signaling information such as CQI indicating thechannel status are transmitted without relation to each other.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

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 9. A method for transmittinguplink information in a Single Carrier Frequency Division MultipleAccess (SC-FDMA) wireless communication system, the method comprisingthe steps of: multiplexing encoded uplink data that is encoded accordingto a first encoding scheme, encoded first uplink signaling informationthat is encoded according a second encoding scheme, and second uplinksignaling information to generate multiplexed data; and transmitting thegenerated multiplexed data through a frequency resource allocated forthe uplink data, wherein transmitting the generated multiplexed dataincludes transmitting the encoded uplink data through a firsttransmission resource and the encoded first uplink information through asecond transmission resource such that the first and second transmissionresources are adjacent to each other with respect to a time domain. 10.The method of claim 9, wherein the first uplink signaling informationincludes ACKnowledgment/Negative ACKnowledgment (ACK/NACK) information.11. The method of claim 10, wherein the second uplink signalinginformation includes Channel Quality Indicator (CQI) information. 12.The method of claim 9, wherein the first uplink signaling information isencoded according to a repetition coding process.
 13. An apparatus fortransmitting uplink information in a Single Carrier Frequency DivisionMultiple Access (SC-FDMA) wireless communication system, the apparatuscomprising: a multiplexer for multiplexing encoded uplink data that isencoded according to a first encoding scheme, encoded first uplinksignaling information that is encoded according a second encodingscheme, and second uplink signaling information to generate multiplexeddata; and a data resource mapper for transmitting the generatedmultiplexed data through a frequency resource allocated for the uplinkdata, wherein transmitting the generated multiplexed data includestransmitting the encoded uplink data through a first transmissionresource and the encoded first uplink information through a secondtransmission resource such that the first and second transmissionresources are adjacent to each other with respect to a time domain. 14.The method of claim 13, wherein the first uplink signaling informationincludes ACKnowledgment/Negative ACKnowledgment (ACK/NACK) information.15. The method of claim 14, wherein the second uplink signalinginformation includes Channel Quality Indicator (CQI) information. 16.The method of claim 13, wherein the first uplink signaling informationis encoded according to a repetition coding process.